Gas purification



Aug. 4, 1925. 1,548,288 H. F. SMITH GAS PURIFICATION Original Filed Dec.19, 1921 i l lw Patented Aug. 4, 1925.

UNITED STATES PATENT OFFICE.

HARRY 1!. SMITH, OF DAYTON, OHIO, ASSIGNOR TO THE GAS RESEARCH COMPANY,

OF DAYTON, OHIO, A CORPORATION OF OHIO.

GAS PURIFICATION.

Application filed December 19, 1921, Serial No. 523,392. Renewed June 8,1925. a

To an whom it may concern:

Be it known that I, HARRY F. SMITH, a citizen of the United States ofAmerica, residing at Dayton, county of Montgomery,

6 and State of Ohio, have invented certain new and useful Improvementsin Gas Purification, of which the following is a full, clear, and exactdescription. This invention relates to purification of 1 gas, andparticularly to the treatment of producer gas to remove impurities suchas tar and the like therefrom.

In the patents issued to Harry F. Smith Numbers 1,099,773 and 1,140,198,bearing datesrespectively of June 9, 191 1 and May 18, 1915, is set outa method of purifying gas andh type of apparatus for carrying 1 thatmethod intov effect. The method of purification therein set out is basedon the fact that if a gas containing impurities therein, such impuritiesfor example as tar,

is passed through a diaphragm of spun glass, or some analogoussubstance, at a suitable velocity, a coalescence or agglomeration of theparticles .of impurity will take place with the. production of particlesof such substantial size that they will readily separate' out under theaction of gravity,'when carried out of the diaphragm by the current ofgas. Experience seems to show thatthe cleaning effectiveness of suchapparatus is in accordance with the velocity of flow of the gas throughthe diaphragm. The greater the velocity of flow the better the cleaning.

tory cleaning under actual operating conditions, it is apparentlynecessary to at all times maintain a minimum velocity of flow. Thevelocity of flow of the gas .within the diaphragm, other conditionsremaining constant, is dependent upon the differential pressure uponopposite sides of the diaphragm, and the cleaning effectiveness is, inpractice, -maintained by socontrolling the cleaning apparatus that thedrop in pressure across the diaphragm shall not, normally,

fall below a predetermined minimum. In practice it has been found that adifferential pressure of substantially two; pounds gives very effectivecleaning, not less than 99.5 per cent of the tar being removed from thegas under these circumstances. Preferably a pressure of substantiallytwo pounds on one side and four pounds on the other side of thediaphragm is maintained, though to the housing 10. An out-let 12,adapted .And in order to secure sufficiently satisfac-' these pressuresmay vary so long as the drop in pressure across the diaphragm does notdepart materially from the desired differential of two pounds, orwhatever differential is found to give the desired cleaningeffectiveness.

. In the patent issued to Harry F. Smith May 24, 1921 No. 1,37 9,056 isillustrated and described one method, and apparatus, for effecting thedesired cleaning of gas. v

One of the principal objects of the. present invention is to provideanother method in connection with this form of purification, by nieansofwhich the desired cleaning effectiveness maybe maintained. Anotherobject of the invention is to provide suitable apparatus for carryingthat method into efiect.

Other objects and advantages of the invention will be apparent from thedescription set out below when taken in connection with the accompanyingdrawing, in which -is illustrated in section, a form of purifyingapparatus embodying this invention.

In the form ofapparatus shown the numeral 10.designates a drum orhousing, having an inlet opening 11, adapted for connection to a mainthrough which the fluid to be cleaned passes from any suitable sourcein- 8 for receiving'the delivery main, through which the gas is led toany desired place of use or storage, is also provided through which thegas which has been treated passes out from the housing. The upper partof the 9 housing is closed by means of a removable cap 13, theconstruction being such that access to the interiorof the housing maybe" readily had upon removal of the'cap. The lower part of the housingis also preferably made detachable, though it may be made integral ifdesired. Suitable packing material maybe interposed between this lowerclosure and the housing, in order to prevent leakage.

Positioned within the housing is a cylindrical sleeve 15, preferably ofperforated sheet metal, a second cylindrical sleeve, 16 also,preferably, of perforated sheet metal, being positioned withinthe sleeve15, the two sleeves being so proportioned that a suitable space isprovided which is adapted to receive spun glass, or other suitable fila'mentous material, which serves as a per- I VlOllS, non-filter1ng,d1aphragm; The sleeve 15 is provided at its upper end without standinglugs 18 having threaded passages therein adapted to receive theadjusting bolts 19, which cooperate with the closure and compressionmember 20, positioned within the space between the two sleeves 15 and16, and, preferably, in'substantially gas tight connectionwith these twosleeves, so that there maybe no leakage of gas upwardly between thesemembers. This member 20 not only serves to thus preventthe escape of gasfrom between the two'sleeves 15 and 16, but also for the primary purposeof compressing the filamentous'inaterial 17 to the desired density.

Slidably mounted within the inside of the inner sleeve 16 is a piston25, which is in substantially gas tight contact with the cooperatingsurface of the sleeve 16, and which is in addition, provided withgrooves 26, throughout its len h, which serve to prevent the passage 0untreated gas from the space 27, within the inside of the diaphragm,upwardly between the piston 25 andvtlie sleeve 16.

'such' as finely spun glass, hair, or the like,

at a suitable velocity, and as the gas passes through the pad ordiaphragm the very finely divided tar fog therein will be so acted uponas to cause the extremely minute tar particles to agglomerate into dropsof subi stantial size, which are carried on out of the diaphragm by theflowing gas and are subsequently separated out through gravity. If thequantity of gas passing through the cleaning apparatus weresubstantially constant, under all conditions, the problem would becomparatively sm all,for the diaphragm having been arranged at adensity' to give the desired differentialpressure on opposite sidesthereof, no further'manipulation of the diaphragm would be necessary,but inactual practice the gas is-subject to minor pressure fluctuationswithoutany material variation in the quantity of gas passingthrough thecleaning apparatus, perhaps as a result of temporary clogging of'a partof the diaphragm, or for other reasons; and in addition the gas is fromtime to time subject to wide variations in the quantity passing throughthe diaphragm, which will in turn be translated into variations in thedifferential pressure upon opposite sides of the diaphragmv unless meansistaken to maintain the differential pressure substan tially constant..l V v In the use of thedescribed apparatus for removing tar fromproducer gas, for exam- -ple, the space between the sleeves 15 and 16 isfilledwith'the desired filamentous mate-' rial, spun glass say, and themember 20 is thenadjusted to give that compremion of the filamentousdiaphragm which is desirable under the normal operating conditions to bemet. When the gas is introduced through the inlet 11 into the space 27under suitable pressure the piston 25 will move upwardly to uncover aportion of the diaphragm, the upward movement of the piston continuinguntil the pressure within the space 27 is such as tobalance the weightof the piston. If the pressure within the space 27 varies as a result ofminor fluctuations during operating conditions, oras a result 10f amaterial change of the quantity of gas being used, or as a resultof'partial clogging of the pad, or for any other reason, the piston 25will assume a new position corresponding to the changed pressure tomaintain that pressure] substantially constant. As a result asubstantially constant differential pressure, upon opposite sides of thediaphragm, will be secured, and the cleaning 'effectiveness oftheapparatus thus main- V tained. As set out above, when impurities,such -as tar and the like, are tobe removed from Inasmuch as thedifferential pressure upon opposite sides of the diaphragm is due to theresistance to flow throu h the diaphragm, and that is controlled y theeffective cross sectional area of the opening through the diaphragm,which-is in turn dependent, under any given-comp'rssion of 'thediaphragm, u 11 the effectiveyor uncoveredfarea of t e diaphragm, thepiston "25 as it moves up or down functions to control the effectivearea of the diaphragm and thus to control the differential pressure onopposite sides thereof, by varying the total effective areaof-the'passa'gesthrough the dia hragm, that is the effectiveo ningthroug the diaphragm. The term e ective' opening through the diaphragm,therefore, is used .todesignate the total cross sectional area, thetotal opening, throughthat part of the diaphragm which is not covered bythe iston and which part is therefore, effective in the cleaning 0eration. a

While the met od herein described, and the form of apparatus forcarrying this method into effect, constitute preferred einbodiinents ofthe invention, it is to be understood that the invention is not limited.to

this precise method and form of apparatus, and that changes may bemadein either without departing from the scope ofthe invention which isdefined in the appended claims.

What is claimed is:

1. 'Ihe method of purifying gas which.

consists in passing the gas through a filamentous'diaphragn and varyingthe effective area'of said diaphragm to keep substantially constant. thedifferential pressure on opposite sides thereof.

2."The method ofpurifying gas which consists in passing the gas througha fila-.

mentous, non-filtering diaphragm; and varying the effective area of saiddiaphragm to pressure on opposite sides thereof.

effectiveness.

- tous iaphiagm eifectiveness.

4:. In a gas purifying system a filamentous, and meansassocinon-filtering, diaphragm; ated. with said diaphragm for varyingthe effective area thereof to control the cleaning 5. In a gas purifyingsystem, a filamentous diaphragm; and means associated with saiddiaphragm for automatically varying the efiective area thereof tocontrol the cleaning 6. In a gas purifying system, a housing having acylindrical non-filtering pervious diaphragm therein, said housinghaving an inlet opening into the space inside the diaphragm and anoutlet opening from the space outside the diaphragm; and a slidablepiston within the diaphragm, the construction being such that theeffective area of the diaphragm is determined by the positioning of saidpiston.

7. In a gas purifying s stem, a housing havin a cylindrical nonltering,filamentherein, said housing having an inlet opening into' the spacewithin the diaphragm and an outlet opening from the space outside thediaphragm; and a slid-' able piston within the diaphragm, theconstruction being such that the effective area spaced walls,

side the perforated walls,

of the diaphragm is determined by the positioning of said piston.

8. In a gas purifying system, a housing having inlet and outletopenings;

opening, filamentous material between said 'means for compressing saidmaterial to give a desired density thereof; and a piston in slidable,and substantially gas tight, contact'within the inner of said spacedwalls, the construction being such that the piston will rise or fallwith fluctuations in the pressure existing within the space intoincrease or decrease the efiective area of filamentous material tomaintain substantially uniform the differential pressure on oppositesides thereof.

9. In a gas purifying system, a housing,

having inlet and outlet openings; spaced 7 spaced perforated wallssurrounding said inlet perforated walls surrounding said inlet opening,filamentous non-filtering. material between said spaced walls, means forcompressing said material to give a desired density thereof; and apiston in slidable, and substantially gas tight, contact within theinner of said spaced walls, the construction being such that the pistonwill rise or fall with fluctuations in the pressure exist-' ing withinthe space inside the perforated walls, to increase or decrease theeffective area of filamentous material to maintain substantially uniformthe cleaning eflectiveness.

In testimony whereof I hereto afiix my signature.

H. G. DUERR, L. G. THOMASSEN.

